/*
 * This is work is derived from material Copyright RSA Data Security, Inc.
 *
 * The RSA copyright statement and Licence for that original material is
 * included below. This is followed by the Apache copyright statement and
 * licence for the modifications made to that material.
 */

/* MD5C.C - RSA Data Security, Inc., MD5 message-digest algorithm
 */

/* Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All
   rights reserved.

   License to copy and use this software is granted provided that it
   is identified as the "RSA Data Security, Inc. MD5 Message-Digest
   Algorithm" in all material mentioning or referencing this software
   or this function.

   License is also granted to make and use derivative works provided
   that such works are identified as "derived from the RSA Data
   Security, Inc. MD5 Message-Digest Algorithm" in all material
   mentioning or referencing the derived work.

   RSA Data Security, Inc. makes no representations concerning either
   the merchantability of this software or the suitability of this
   software for any particular purpose. It is provided "as is"
   without express or implied warranty of any kind.

   These notices must be retained in any copies of any part of this
   documentation and/or software.
 */

/* ====================================================================
 * Copyright (c) 1996-1998 The Apache Group.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the Apache Group
 *    for use in the Apache HTTP server project (http://www.apache.org/)."
 *
 * 4. The names "Apache Server" and "Apache Group" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Group.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the Apache Group
 *    for use in the Apache HTTP server project (http://www.apache.org/)."
 *
 * THIS SOFTWARE IS PROVIDED BY THE APACHE GROUP ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE APACHE GROUP OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Group and was originally based
 * on public domain software written at the National Center for
 * Supercomputing Applications, University of Illinois, Urbana-Champaign.
 * For more information on the Apache Group and the Apache HTTP server
 * project, please see <http://www.apache.org/>.
 *
 */

#include <string.h>

#include "conf.h"
#include "ap_md5.h"
#ifdef CHARSET_EBCDIC
#include "ebcdic.h"
#endif /*CHARSET_EBCDIC*/

/* Constants for MD5Transform routine.
 */

#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21

static void MD5Transform(UINT4 state[4], const unsigned char block[64]);
static void Encode(unsigned char *output, const UINT4 *input,
		   unsigned int len);
static void Decode(UINT4 *output, const unsigned char *input,
		   unsigned int len);

static unsigned char PADDING[64] =
{
    0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};

/* F, G, H and I are basic MD5 functions.
 */
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))

/* ROTATE_LEFT rotates x left n bits.
 */
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

/* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
   Rotation is separate from addition to prevent recomputation.
 */
#define FF(a, b, c, d, x, s, ac) { \
 (a) += F ((b), (c), (d)) + (x) + (UINT4)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }
#define GG(a, b, c, d, x, s, ac) { \
 (a) += G ((b), (c), (d)) + (x) + (UINT4)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }
#define HH(a, b, c, d, x, s, ac) { \
 (a) += H ((b), (c), (d)) + (x) + (UINT4)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }
#define II(a, b, c, d, x, s, ac) { \
 (a) += I ((b), (c), (d)) + (x) + (UINT4)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }

/* MD5 initialization. Begins an MD5 operation, writing a new context.
 */
API_EXPORT(void) ap_MD5Init(AP_MD5_CTX * context)
{
    context->count[0] = context->count[1] = 0;
    /* Load magic initialization constants. */
    context->state[0] = 0x67452301;
    context->state[1] = 0xefcdab89;
    context->state[2] = 0x98badcfe;
    context->state[3] = 0x10325476;
}

/* MD5 block update operation. Continues an MD5 message-digest
   operation, processing another message block, and updating the
   context.
 */
API_EXPORT(void) ap_MD5Update(AP_MD5_CTX * context, const unsigned char *input,
			   unsigned int inputLen)
{
    unsigned int i, idx, partLen;

    /* Compute number of bytes mod 64 */
    idx = (unsigned int) ((context->count[0] >> 3) & 0x3F);

    /* Update number of bits */
    if ((context->count[0] += ((UINT4) inputLen << 3)) < ((UINT4) inputLen << 3))
	context->count[1]++;
    context->count[1] += (UINT4) inputLen >> 29;

    partLen = 64 - idx;

    /* Transform as many times as possible. */
#ifndef CHARSET_EBCDIC
    if (inputLen >= partLen) {
	memcpy(&context->buffer[idx], input, partLen);
	MD5Transform(context->state, context->buffer);

	for (i = partLen; i + 63 < inputLen; i += 64)
	    MD5Transform(context->state, &input[i]);

	idx = 0;
    }
    else
	i = 0;

    /* Buffer remaining input */
    memcpy(&context->buffer[idx], &input[i], inputLen - i);
#else /*CHARSET_EBCDIC*/
    if (inputLen >= partLen) {
	ebcdic2ascii_strictly(&context->buffer[idx], input, partLen);
	MD5Transform(context->state, context->buffer);

	for (i = partLen; i + 63 < inputLen; i += 64) {
	    unsigned char inp_tmp[64];
	    ebcdic2ascii_strictly(inp_tmp, &input[i], 64);
	    MD5Transform(context->state, inp_tmp);
	}

	idx = 0;
    }
    else
	i = 0;

    /* Buffer remaining input */
    ebcdic2ascii_strictly(&context->buffer[idx], &input[i], inputLen - i);
#endif /*CHARSET_EBCDIC*/
}

/* MD5 finalization. Ends an MD5 message-digest operation, writing the
   the message digest and zeroizing the context.
 */
API_EXPORT(void) ap_MD5Final(unsigned char digest[16], AP_MD5_CTX * context)
{
    unsigned char bits[8];
    unsigned int idx, padLen;


    /* Save number of bits */
    Encode(bits, context->count, 8);

#ifdef CHARSET_EBCDIC
    /* XXX: @@@: In order to make this no more complex than necessary,
     * this kludge converts the bits[] array using the ascii-to-ebcdic
     * table, because the following ap_MD5Update() re-translates
     * its input (ebcdic-to-ascii).
     * Otherwise, we would have to pass a "conversion" flag to ap_MD5Update()
     */
    ascii2ebcdic(bits,bits,8);

    /* Since everything is converted to ascii within ap_MD5Update(), 
     * the initial 0x80 (PADDING[0]) must be stored as 0x20 
     */
    PADDING[0] = os_toebcdic[0x80];
#endif /*CHARSET_EBCDIC*/

    /* Pad out to 56 mod 64. */
    idx = (unsigned int) ((context->count[0] >> 3) & 0x3f);
    padLen = (idx < 56) ? (56 - idx) : (120 - idx);
    ap_MD5Update(context, PADDING, padLen);

    /* Append length (before padding) */
    ap_MD5Update(context, bits, 8);

    /* Store state in digest */
    Encode(digest, context->state, 16);

    /* Zeroize sensitive information. */
    memset(context, 0, sizeof(*context));
}

/* MD5 basic transformation. Transforms state based on block. */
static void MD5Transform(UINT4 state[4], const unsigned char block[64])
{
    UINT4 a = state[0], b = state[1], c = state[2], d = state[3], x[16];

    Decode(x, block, 64);

    /* Round 1 */
    FF(a, b, c, d, x[0], S11, 0xd76aa478);	/* 1 */
    FF(d, a, b, c, x[1], S12, 0xe8c7b756);	/* 2 */
    FF(c, d, a, b, x[2], S13, 0x242070db);	/* 3 */
    FF(b, c, d, a, x[3], S14, 0xc1bdceee);	/* 4 */
    FF(a, b, c, d, x[4], S11, 0xf57c0faf);	/* 5 */
    FF(d, a, b, c, x[5], S12, 0x4787c62a);	/* 6 */
    FF(c, d, a, b, x[6], S13, 0xa8304613);	/* 7 */
    FF(b, c, d, a, x[7], S14, 0xfd469501);	/* 8 */
    FF(a, b, c, d, x[8], S11, 0x698098d8);	/* 9 */
    FF(d, a, b, c, x[9], S12, 0x8b44f7af);	/* 10 */
    FF(c, d, a, b, x[10], S13, 0xffff5bb1);	/* 11 */
    FF(b, c, d, a, x[11], S14, 0x895cd7be);	/* 12 */
    FF(a, b, c, d, x[12], S11, 0x6b901122);	/* 13 */
    FF(d, a, b, c, x[13], S12, 0xfd987193);	/* 14 */
    FF(c, d, a, b, x[14], S13, 0xa679438e);	/* 15 */
    FF(b, c, d, a, x[15], S14, 0x49b40821);	/* 16 */

    /* Round 2 */
    GG(a, b, c, d, x[1], S21, 0xf61e2562);	/* 17 */
    GG(d, a, b, c, x[6], S22, 0xc040b340);	/* 18 */
    GG(c, d, a, b, x[11], S23, 0x265e5a51);	/* 19 */
    GG(b, c, d, a, x[0], S24, 0xe9b6c7aa);	/* 20 */
    GG(a, b, c, d, x[5], S21, 0xd62f105d);	/* 21 */
    GG(d, a, b, c, x[10], S22, 0x2441453);	/* 22 */
    GG(c, d, a, b, x[15], S23, 0xd8a1e681);	/* 23 */
    GG(b, c, d, a, x[4], S24, 0xe7d3fbc8);	/* 24 */
    GG(a, b, c, d, x[9], S21, 0x21e1cde6);	/* 25 */
    GG(d, a, b, c, x[14], S22, 0xc33707d6);	/* 26 */
    GG(c, d, a, b, x[3], S23, 0xf4d50d87);	/* 27 */
    GG(b, c, d, a, x[8], S24, 0x455a14ed);	/* 28 */
    GG(a, b, c, d, x[13], S21, 0xa9e3e905);	/* 29 */
    GG(d, a, b, c, x[2], S22, 0xfcefa3f8);	/* 30 */
    GG(c, d, a, b, x[7], S23, 0x676f02d9);	/* 31 */
    GG(b, c, d, a, x[12], S24, 0x8d2a4c8a);	/* 32 */

    /* Round 3 */
    HH(a, b, c, d, x[5], S31, 0xfffa3942);	/* 33 */
    HH(d, a, b, c, x[8], S32, 0x8771f681);	/* 34 */
    HH(c, d, a, b, x[11], S33, 0x6d9d6122);	/* 35 */
    HH(b, c, d, a, x[14], S34, 0xfde5380c);	/* 36 */
    HH(a, b, c, d, x[1], S31, 0xa4beea44);	/* 37 */
    HH(d, a, b, c, x[4], S32, 0x4bdecfa9);	/* 38 */
    HH(c, d, a, b, x[7], S33, 0xf6bb4b60);	/* 39 */
    HH(b, c, d, a, x[10], S34, 0xbebfbc70);	/* 40 */
    HH(a, b, c, d, x[13], S31, 0x289b7ec6);	/* 41 */
    HH(d, a, b, c, x[0], S32, 0xeaa127fa);	/* 42 */
    HH(c, d, a, b, x[3], S33, 0xd4ef3085);	/* 43 */
    HH(b, c, d, a, x[6], S34, 0x4881d05);	/* 44 */
    HH(a, b, c, d, x[9], S31, 0xd9d4d039);	/* 45 */
    HH(d, a, b, c, x[12], S32, 0xe6db99e5);	/* 46 */
    HH(c, d, a, b, x[15], S33, 0x1fa27cf8);	/* 47 */
    HH(b, c, d, a, x[2], S34, 0xc4ac5665);	/* 48 */

    /* Round 4 */
    II(a, b, c, d, x[0], S41, 0xf4292244);	/* 49 */
    II(d, a, b, c, x[7], S42, 0x432aff97);	/* 50 */
    II(c, d, a, b, x[14], S43, 0xab9423a7);	/* 51 */
    II(b, c, d, a, x[5], S44, 0xfc93a039);	/* 52 */
    II(a, b, c, d, x[12], S41, 0x655b59c3);	/* 53 */
    II(d, a, b, c, x[3], S42, 0x8f0ccc92);	/* 54 */
    II(c, d, a, b, x[10], S43, 0xffeff47d);	/* 55 */
    II(b, c, d, a, x[1], S44, 0x85845dd1);	/* 56 */
    II(a, b, c, d, x[8], S41, 0x6fa87e4f);	/* 57 */
    II(d, a, b, c, x[15], S42, 0xfe2ce6e0);	/* 58 */
    II(c, d, a, b, x[6], S43, 0xa3014314);	/* 59 */
    II(b, c, d, a, x[13], S44, 0x4e0811a1);	/* 60 */
    II(a, b, c, d, x[4], S41, 0xf7537e82);	/* 61 */
    II(d, a, b, c, x[11], S42, 0xbd3af235);	/* 62 */
    II(c, d, a, b, x[2], S43, 0x2ad7d2bb);	/* 63 */
    II(b, c, d, a, x[9], S44, 0xeb86d391);	/* 64 */

    state[0] += a;
    state[1] += b;
    state[2] += c;
    state[3] += d;

    /* Zeroize sensitive information. */
    memset(x, 0, sizeof(x));
}

/* Encodes input (UINT4) into output (unsigned char). Assumes len is
   a multiple of 4.
 */
static void Encode(unsigned char *output, const UINT4 *input, unsigned int len)
{
    unsigned int i, j;
    UINT4 k;

    for (i = 0, j = 0; j < len; i++, j += 4) {
	k = input[i];
	output[j] = (unsigned char) (k & 0xff);
	output[j + 1] = (unsigned char) ((k >> 8) & 0xff);
	output[j + 2] = (unsigned char) ((k >> 16) & 0xff);
	output[j + 3] = (unsigned char) ((k >> 24) & 0xff);
    }
}

/* Decodes input (unsigned char) into output (UINT4). Assumes len is
   a multiple of 4.
 */
static void Decode(UINT4 *output, const unsigned char *input, unsigned int len)
{
    unsigned int i, j;

    for (i = 0, j = 0; j < len; i++, j += 4)
	output[i] = ((UINT4) input[j]) | (((UINT4) input[j + 1]) << 8) |
	    (((UINT4) input[j + 2]) << 16) | (((UINT4) input[j + 3]) << 24);
}
